Mammalia Linnaeus 1758 [Rowe 1988], nom. cl. inval.
 see Clade Mammalia Linnaeus 1758 [Rowe 2020]
  
 Metatheria Huxley 1880 [O'Leary, Allard, Novacek, Meng & Gatesy 2004]
 see Infraclass Metatheria Huxley, 1880
    
 Marsupialiformes Vullo, Gheerbrant, de Muizon & Néraudeau, 2009
      
 [Order] †Alphadontia Archer, 1984
        
 [Suborder] †Hatcheriformes Case, Goin & Woodburne, 2005
          
 1 Family †Ectocentrocristidae [monotypic]
          
 2.1.1 Genus †Zeusdelphys Marshall, 1987
          
 2.1.2 Genus †Hatcheritherium Case, Goin & Woodburne, 2004
          
 2.2.1.1 Genus †Xenostylus Goin, Case, Woodburne, Vizcaino & Reguero, 1999, nom. illeg.
          
 2.2.1.2 †"Varalphadon" crebreforme (Cifelli, 1990)
          
 2.2.2 Subfamily †Chulpasiinae Sigé et al., 2009
          
 2.2.3.1 Genus †Mirandatherium Paula Couto, 1952
          
 2.2.3.2.1.1 Genus †Bobbschaefferia Paula Couto, 1970
          
 2.2.3.2.1.2 Genus †Wirunodon Goin & Candela, 2004
          
 2.2.3.2.2 Family †Caroloameghiniidae Ameghino, 1901